97 SJ starving for fuel???

blastin603

blastin603

Location
new hampshire
i have a freshly built 97 SJ. has a blowsion head (175psi) bpipe, msd enchancer. stock 38 carbs with 95g springs 70 lows and 135 highs.. It runs absolutely flawless for about 20 mins. out of nowhere no matter what thpe of riding im doing... freestyle or just bombing around. it starts hesitating.. only thing that helps it is hiting primer.. it gradually gets worse untill you can really only limp back to shore. if i pull off the fuel feed to the carbs.. it feels like there is resistance if i try to suck fuel.. if i blows bubles in tank back thru line.. i can suck and it flows easily. i replaced the fuel vent valve. and actually tried riding around with the vent tube off and same thing... and its not overheating.. i have a new inline filter that isnt clogged. carbs were cleaned
 
amitchell

amitchell

Location
Victoria BC
blastin603 said:
i have a freshly built 97 SJ. has a blowsion head (175psi) bpipe, msd enchancer. stock 38 carbs with 95g springs 70 lows and 135 highs.. It runs absolutely flawless for about 20 mins. out of nowhere no matter what thpe of riding im doing... freestyle or just bombing around. it starts hesitating.. only thing that helps it is hiting primer.. it gradually gets worse untill you can really only limp back to shore. if i pull off the fuel feed to the carbs.. it feels like there is resistance if i try to suck fuel.. if i blows bubles in tank back thru line.. i can suck and it flows easily. i replaced the fuel vent valve. and actually tried riding around with the vent tube off and same thing... and its not overheating.. i have a new inline filter that isnt clogged. carbs were cleaned
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Did you rebuild the carbs? check your pulse line and carb pump valves for creases or tears? Did you ride with the vent tube off AND the new tank vent valve off? could the new valve be bad?

Are you sure its a fuel problem and not an electrical problem? Sometimes when things warm up the stator/coil can go funny.
 
blastin603

blastin603

Location
new hampshire
well everything in the ski came out of my running mint waveraider. with exception of msd... when i blow in line and take it back out immediately after its good for another 15-20 mins..
 
amitchell

amitchell

Location
Victoria BC
When you blow in are you pressurizing the tank and putting the line back on while the tank is still pressurized? I would look at the fuel pump check valves and pulse line then.
 
blastin603

blastin603

Location
new hampshire
i used all new fuel lines.. i didnt rebuild the carbs with new seals and whatnot. but everything looked find and was riding that waveraider with no issues a couple weeks ago. i guess ill try bypassing the fuel filter. just strange it runs mint for 20 mins.. then barely runs at all
 
Crab

Crab

thanks darin...noswad!
Location
Seattle
Did you check in carb filters? be sure and run fuel straight from the tank to the carbs (inline filter ok) and eliminate the reserve switch.
 
blastin603

blastin603

Location
new hampshire
Crab said:
Did you check in carb filters? be sure and run fuel straight from the tank to the carbs (inline filter ok) and eliminate the reserve switch.
Click to expand...
running straight from reserve to inline filter to carbs.. inspected pickup in line in tank. cleaned the carb filters when i did jets and spring
 
blastin603

blastin603

Location
new hampshire
hmmm not sure why. but i bypassed the brand new inline fuel filter and just went thru 3 gallons with no issues. it actually seemed to richen up the low end also..
 
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